A friend of my got the following error in his log when he joins the server.
[ 122860] CfxCollection[dlc.rpf]::AllocateHandle got passed a failed handle for dlc_mpLowrider:/x64/data/cacheLoaderData_DLC/mpLowrider_1924616720_cache_y.dat
[ 123516] CfxCollection[dlc.rpf]::AllocateHandle got passed a failed handle for dlc_mpLowrider:/x64/data/cacheLoaderData_DLC/mpLowrider_1289734211_cache_y.dat
[ 127047] CfxCollection[dlc.rpf]::AllocateHandle got passed a failed handle for dlc_mpLowrider:/x64/data/cacheLoaderData_DLC/mpLowrider_847561697_cache_y.dat
[ 127907] CfxCollection[dlc.rpf]::AllocateHandle got passed a failed handle for dlc_mpLowrider:/x64/data/cacheLoaderData_DLC/mpLowrider_484579484_cache_y.dat
[ 128735] CfxCollection[dlc.rpf]::AllocateHandle got passed a failed handle for dlc_mpExecutive:/x64/data/cacheLoaderData_DLC/mpExecutive_2038425240_cache_y.dat